Question

A spring with a constant of `6` `kgs^-2` is lying on the ground with one end attached to a wall. An object with a mass of `3` `kg` and speed of `4` `ms^-1` collides with and compresses the spring until it stops moving. How much will the spring compress?

Answer 1

The kinetic energy of the moving object, `E_k=1/2mv^2=1/2*3*4^2=24` `J`, will be converted into spring potential energy, `E_p=1/2kx^2`. Rearranging, `x=sqrt((2E_p)/k)=sqrt(2*24)/6=sqrt8` `m`.